winbox and webfig - rb433 and v6.0

RB433 - ospf router mode - V6.0
At 1.48 minutes to lift the wlan link, stop working and webfig winbox services.
It is only accessible by telnet mac.
It responds to ping. Pppoe connections and normal traffic

With the RB493 is the same.
With the RB133 Connection is lost.
With the RB493G everything right, accessed by ethernet.
No problem with RB711-5HnD
In all cases of V5.25 migrated to V6.0